The grounding occurred after the two switches in the battery room were mistakenly put in the OFF position. Some consideration therefore must be given to the location of the vital switches, their marking and the crew familiarization. Every electrical circuit must be equipped with switches and breakers designed to interrupt the power supply. However, such switches, especially those guarding vital circuits, must be clearly marked and protected against accidental use. The two important switches on the MAYNE QUEEN were located in a compartment that was padlocked to prevent passengers from entering it. However, the fact that there was an unknown number of keys to this padlock in the hands of various crew members and there was no additional protection of the switches, made these switches susceptible to accidental use. The third engineer had used the two switches to de-activate the vessel during graveyard shifts, but he was not familiar with the battery-testing procedure nor did he know how the chief engineer intended to carry out the test. This lack of familiarity may be attributed to the fact that these two individuals had never sailed together on this ship previously. Furthermore, as the tests were conducted on Mondays only, it was the first time that the third engineer had participated in one of them. The third engineer, who knew how to disconnect the power supply, assumed that putting the switches in the OFF position would be the procedure to use to perform the battery test. It seems that the familiarization process was not thorough, and that, in particular, no discussion had taken place between the chief and third engineers regarding the standard method of performing the battery test. This inadequacy may have been compounded by the fact that the crews are often transferred from one vessel to another. The master had a crucial and difficult decision to make: either use the jog steering to turn the vessel away from the reef or stop her before she ran aground. Turning the RADs blindly, without knowing their actual direction, carried the risk of increasing the vessel's speed toward the shallow water when there was no room to make the attempt and observe the vessel's reaction. Declutching the RADs and dropping both anchors, thus decreasing the momentum, is considered to have been the proper and justified action in the circumstances.Analysis The grounding occurred after the two switches in the battery room were mistakenly put in the OFF position. Some consideration therefore must be given to the location of the vital switches, their marking and the crew familiarization. Every electrical circuit must be equipped with switches and breakers designed to interrupt the power supply. However, such switches, especially those guarding vital circuits, must be clearly marked and protected against accidental use. The two important switches on the MAYNE QUEEN were located in a compartment that was padlocked to prevent passengers from entering it. However, the fact that there was an unknown number of keys to this padlock in the hands of various crew members and there was no additional protection of the switches, made these switches susceptible to accidental use. The third engineer had used the two switches to de-activate the vessel during graveyard shifts, but he was not familiar with the battery-testing procedure nor did he know how the chief engineer intended to carry out the test. This lack of familiarity may be attributed to the fact that these two individuals had never sailed together on this ship previously. Furthermore, as the tests were conducted on Mondays only, it was the first time that the third engineer had participated in one of them. The third engineer, who knew how to disconnect the power supply, assumed that putting the switches in the OFF position would be the procedure to use to perform the battery test. It seems that the familiarization process was not thorough, and that, in particular, no discussion had taken place between the chief and third engineers regarding the standard method of performing the battery test. This inadequacy may have been compounded by the fact that the crews are often transferred from one vessel to another. The master had a crucial and difficult decision to make: either use the jog steering to turn the vessel away from the reef or stop her before she ran aground. Turning the RADs blindly, without knowing their actual direction, carried the risk of increasing the vessel's speed toward the shallow water when there was no room to make the attempt and observe the vessel's reaction. Declutching the RADs and dropping both anchors, thus decreasing the momentum, is considered to have been the proper and justified action in the circumstances. The power supply to the steering system was disconnected while the vessel was under way and turning to port, when two switches in the electrical circuit of the power supply were mistakenly turned off by the third engineer during a weekly battery test. The third engineer was not familiar with the battery-testing procedure on this vessel. The vessel, without any steering, kept swinging to port until she grounded on a nearby reef. The master attempted to avoid grounding by stopping the propulsion and dropping the anchors. These actions appear to have been appropriate measures in the circumstances. All actions following the grounding, up to and including refloating, taken by the master, the crew and the owners were timely and appropriate in the circumstances. The ferry's propulsion units sustained extensive damage. The passengers were looked after by personnel and kept informed.Findings The power supply to the steering system was disconnected while the vessel was under way and turning to port, when two switches in the electrical circuit of the power supply were mistakenly turned off by the third engineer during a weekly battery test. The third engineer was not familiar with the battery-testing procedure on this vessel. The vessel, without any steering, kept swinging to port until she grounded on a nearby reef. The master attempted to avoid grounding by stopping the propulsion and dropping the anchors. These actions appear to have been appropriate measures in the circumstances. All actions following the grounding, up to and including refloating, taken by the master, the crew and the owners were timely and appropriate in the circumstances. The ferry's propulsion units sustained extensive damage. The passengers were looked after by personnel and kept informed. The MAYNEQUEEN experienced a steering failure, veered to port and entered shallow water. Although the RADs were declutched and both the bow and stern anchors were dropped, these measures did not stop the vessel running aground. The steering failure occurred when the power supply to the main steering control system was disconnected during a routine test of the control unit batteries. The third engineer, participating in the test without the chief engineer's knowledge, was insufficiently trained in battery-testing procedures.Causes and Contributing Factors The MAYNEQUEEN experienced a steering failure, veered to port and entered shallow water. Although the RADs were declutched and both the bow and stern anchors were dropped, these measures did not stop the vessel running aground. The steering failure occurred when the power supply to the main steering control system was disconnected during a routine test of the control unit batteries. The third engineer, participating in the test without the chief engineer's knowledge, was insufficiently trained in battery-testing procedures. Following this occurrence, the owners modified both the switches and the testing procedure on the MAYNEQUEEN and the BOWEN QUEEN as follows: each of the two main switches is fitted with a lock; red labels with warnings are placed next to the switches; a spare key to the battery compartment has been placed by the door in a glass box; the battery tests are conducted at dock side; and jog steering indicators were installed.Safety Action Taken Following this occurrence, the owners modified both the switches and the testing procedure on the MAYNEQUEEN and the BOWEN QUEEN as follows: each of the two main switches is fitted with a lock; red labels with warnings are placed next to the switches; a spare key to the battery compartment has been placed by the door in a glass box; the battery tests are conducted at dock side; and jog steering indicators were installed.